Method of making carbons



Patented Dec. 30, 1924.

UNITED STATES YOSHIHO INAIDA, OF TAKAW, FOBMOSA, JAPAN.

METHOD OF MAKING GABBONS.

Io Drawing. Application filed September To all whom it may concern:

Be it known that I, YOSHIHO I'NADA, subjectof the Emperor of J a an, residing at 193 vMinato-chio, Takaw, ormosa, Japan,

have invented certain new and useful Improvements in Methods of Making Oarbons, of which the following is a specification.

This invention relates to a method for making carbon for decolorization and has for its object to drive out the volatile matters by stirring and heating a fragrant resiniferous wood to such an extent that it does not become'charred, and consists of im regnating the same with a soluble ma- 16 terlal, and then heating the material to be carbonized to a high temperature in absence of air, washing the material with hot water, then acid, and finally the refining processes are carried on.

A further object of the invention is to get the most eficient carbon for absorbing the coloring matters and impurities contained in cane juice or su ar liquors, and not only the sugar liquors, ut also glucose solution, glycerine, vinegar and the like. I

The treatment drives a fragrant volatile resin entirely out of saw-dust or wood-chips of Hempaku (Ohamaecypam's obtuse) Beni- Hinoki (a kind of aha/maeoypm'is pz'sifem) so of Mt. Ari, or the like and comprises stirring and gently heatin of the material to such an extent that it oes not char: impregnate the material with a solution of an easily soluble salt such for instance as potassium acetate: drying the material: carbonizing the material at a high temperature in the absence of air: soaking the carbonized material in hot water and then acid to dissolve the impurities; subjecting the material to an washing and refining processes and finally again heatin thereby producing a pure car- ''-bon for deco orization.

The following is the details of this invention as an example.

(1) Process of removing volatile resin: The saw dust or wood chips of Hempaku or Beni-Hinoki of Mt. Ari is put into a vessel, stirred gently and heated to such an extent that the material is not charred and so to drive out the fr ant volatile resin.

(2) The material 1s impregnated with alkaline salts: The saw dust heated as above is mixed well with an alkaline salt (such as tassium acetate) in a thicksolution. It wil be seen that the alkaline salts will enter minute pores in the wood. The proportion desired.

8, 1920. Serial No. 408,977.

be mixed with the of potassium acetate to The saw dust presaw dust is as follows. viously heated, one hundred parts. Potassium acetate, forty parts. After impregnation the material is heated until dry, care being taken that it does not ignite.-

(3) Process of carbonizing: The dried saw dust treated as above set forth is then put into a gas retort for carbonization, where the material is heated at 450 C. for the first one hour, then at about 1000 C. for the-second hour, without any quantity of air entering the 'retort and is then taken out exposed to the air a few minutes, and then cooled in a closed vessel.

(4) Process of powdering: The carbon after being cooled is ound to a fine powder in pre aration for t e next treatment.

(5) rocess of washing with water: To remove all the materials soluble in water, the powdered carbon is supplied with water, and then pumped into a filter press to se arate the water which dissolved those so uble salts or the like contained in the raw carbon.

(6) Process of washing with acetic acid: The material not being free from some salts which are not soluble in water, the washed carbon is laced in a wooden tank and then a weak so ution of acid is added such for instance as acetic acid, which is a by-prodnot obtained in certain quantities during the process of carbonizing until it is slightly acid. The material is stirred for about 48 hours to eliminate soluble salts or the like. Then the mixture is heated to a boiling state in the tank by steam jets before pumping into another filter press in which the superfluous water is separated and the material washed well with hot water and later with steam until the filtrate is substantially pure.

(7 Process of finishing: To finish the refimng of the carbon in the filter press, the material is finally pumped through a quantity of pure water containing a small amount of ammonia, and then ,throu h pure water alone. The carbon becomes a ost pure and the last traces oi acid are some acetates.

(8) Process of drying: The carbon comes from the filter press, is transferred into a grediger and then into a closed steel kettle eate by direct fire where the carbon becomes red hot for a while and is then cooled in a vacuum. It may then be packed as (9) Process of recovery of by-products:

' With the gases from the retort during the carbonization operation, two products are separated, one a noncondensib-le gas and the ot er avfiuid.

The noncondensible gas is sent to a gas holder and then to the furnace of the retort as fuel. From the fluid by-products such as acetic acid, wood sprits are recovered and others separately by well known methods such as cooling or distilling. The acetic acid may be used in the washing process.

A thick solution of alkaline salts is obtained by concentrating the filtrate obtained during the process of washing with water and acetic acid and they are utilized in the process of impregnating.

By the above mentioned method of manufacturing the carbon is finished, and the quantity of the carbon is about of the raw material, (saw dust).

here sugar liquor is used it has been found that the carbon obtained has a prompt settling and strong decolorizing property and makes filtration easy. Its decolorizing power is so strong that even by using only 1.5% by weight of carbonfor the total solid matter in the sugar liquor, an absolutely clear bright liquor may be obtained.

This carbon can revivify the decolorizing power by treating with caustic soda and can be repeatedly used.

Compared with other carbons for decolorization, which impregnate chemicals directly into raw materials such for instance? as saw dust, without previously heating the carbon is obtained by the present method and is stronger in decolorizing and makes the filtrate more brilliant. Comparing the carbon made by themethod of this invention with any other. carbon which is obtained from coniferous trees but not having a fragrant volatile resin, the decolorization by the present method is far better than in the methods now in use, and therefore the use of coniferous trees which abound in a fragrant volatile resin is essential for the preparation of decolorizing carbon: Although coniferous trees are used which abound in fragrant volatile resin, if the process of driving away the volatile matters by heating before impregnation is neglected the carbon obtained is the same as carbon obtained by the use of ordinary pine trees. On the contrary if ordinary pine trees are subjected to treatment under the present method the-carbon obtained is more powerful in the point of filtration and decolorization than carbon which does not drive away the volatile matters before decarbonization, therefore the process of driving out the volatile matter, by heating, before impregnation of soluble salts isvery im ortant in the manufacture of carbon for ecolorization.

The invention having been set forth what is claimed as new and useful is A method of obtaining a decolorizing carbon bytreating Japanese coniferous wood having a fragrant volatile resin, said method comprising first driving out the volatile material by heat; impregnating the in presence of two Witnesses.

-YOSHIHO INADA. Witnesses KUYOSHI YOSHIDA, CHUHEE MATSUO. 

